Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A77C11

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N58101 · BOEING 757-200 · operated by UNITED AIRLINES INC

Hex
A77C11
Octal
51676021
Decimal
10,976,273
Country
US
Tail
N58101
Type
B752
No current signal · last broadcast 3d ago
Flights observed
235
Distinct callsigns
20
Country
US
Last broadcast
3d ago

Last known position

Most recent position reported by Mode-S A77C11.

Country allocation

The ICAO 24-bit address A77C11 falls within the block assigned to United States (US) by ICAO Annex 10, Volume III. Every aircraft registered in United States receives a permanent address from this block at the time of registration; the address stays with the airframe even if the aircraft is re-registered to a different operator within the country.

Callsign history 20 distinct

Callsign Airline Flights Last seen
UAL316 - 12 2026-07-04
UAL270 - 11 2026-06-15
UAL271 United Airlines 10 2026-06-15
UAL912 - 9 2026-07-08
UAL310 - 8 2026-07-08
UAL913 - 7 2026-07-02
UAL317 - 7 2026-07-04
UAL311 - 7 2026-07-09
UAL1340 United Airlines 6 2026-05-26
UAL979 - 5 2026-07-10
UAL698 - 5 2026-06-22
UAL661 United Airlines 5 2026-07-07
UAL2743 - 5 2026-06-29
UAL978 - 4 2026-07-10
UAL886 United Airlines 4 2026-06-24
UAL648 - 4 2026-06-25
UAL419 United Airlines 4 2026-06-13
UAL1970 United Airlines 4 2026-06-02
UAL1597 - 4 2026-06-14
UAL145 - 4 2026-07-07

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-10 UAL979 - Jul 10, 12:25 UTCJul 10, 20:15 UTC7h 50m
2026-07-10 UAL979 EDI → IAD Jul 10, 12:30 UTCJul 10, 20:03 UTC7h 33m
2026-07-10 UAL978 IAD → EDI Jul 10, 03:50 UTCJul 10, 10:10 UTC6h 20m
2026-07-09 UAL311 DUB → IAD Jul 9, 08:20 UTCJul 9, 15:30 UTC7h 10m
2026-07-08 UAL310 IAD → DUB Jul 8, 23:50 UTCJul 9, 06:15 UTC6h 25m
2026-07-08 UAL399 KEF → IAD Jul 8, 11:40 UTCJul 8, 17:35 UTC5h 55m
2026-07-08 UAL912 - Jul 8, 03:45 UTCJul 8, 09:20 UTC5h 35m
2026-07-07 UAL661 ORD → EWR Jul 7, 21:45 UTCJul 7, 23:50 UTC2h 5m
2026-07-07 UAL145 OPO → EWR Jul 7, 12:00 UTCJul 7, 19:04 UTC7h 4m
2026-07-07 UAL145 OPO → EWR Jul 7, 12:00 UTCJul 7, 19:05 UTC7h 5m
2026-07-07 UAL144 EWR → OPO Jul 7, 02:45 UTCJul 7, 09:05 UTC6h 20m
2026-07-06 UAL139 KEF → EWR Jul 6, 11:39 UTCJul 6, 16:56 UTC5h 17m
2026-07-06 UAL139 KEF → EWR Jul 6, 11:35 UTCJul 6, 17:00 UTC5h 25m
2026-07-06 UAL138 - Jul 6, 02:30 UTCJul 6, 07:20 UTC4h 50m
2026-07-04 UAL316 DUB → EWR Jul 4, 14:10 UTCJul 4, 21:10 UTC7h 0m
2026-07-04 UAL317 EWR → DUB Jul 4, 06:10 UTCJul 4, 12:05 UTC5h 55m
2026-07-04 UAL2759 - Jul 4, 02:00 UTCJul 4, 03:35 UTC1h 35m
2026-07-04 UAL2759 ORD → EWR Jul 4, 01:29 UTCJul 4, 03:31 UTC2h 2m
2026-07-03 UAL289 - Jul 3, 08:40 UTCJul 3, 16:40 UTC8h 0m
2026-07-03 UAL289 SNN → ORD Jul 3, 08:47 UTCJul 3, 16:17 UTC7h 30m
2026-07-03 UAL288 ORD → SNN Jul 3, 00:05 UTCJul 3, 06:17 UTC6h 12m
2026-07-02 UAL288 - Jul 2, 23:50 UTCJul 3, 00:55 UTC1h 5m
2026-07-02 UAL913 KEF → ORD Jul 2, 12:29 UTCJul 2, 18:19 UTC5h 50m
2026-07-02 UAL913 - Jul 2, 12:20 UTCJul 2, 18:35 UTC6h 15m
2026-07-02 UAL912 ORD → KEF Jul 2, 03:05 UTCJul 2, 08:45 UTC5h 40m
2026-07-01 UAL661 ORD → EWR Jul 1, 21:20 UTCJul 1, 23:30 UTC2h 10m
2026-06-30 UAL282 FAO → EWR Jun 30, 11:01 UTCJun 30, 18:36 UTC7h 35m
2026-06-30 UAL282 FAO → EWR Jun 30, 11:01 UTCJun 30, 18:30 UTC7h 29m
2026-06-30 UAL282 - Jun 30, 11:00 UTCJun 30, 11:55 UTC55m
2026-06-30 UAL281 EWR → FAO Jun 30, 01:25 UTCJun 30, 08:12 UTC6h 47m
2026-06-30 UAL281 EWR → FAO Jun 30, 01:40 UTCJun 30, 08:20 UTC6h 40m
2026-06-29 UAL2743 - Jun 29, 14:04 UTCJun 29, 18:14 UTC4h 10m
2026-06-29 UAL2743 LAX → EWR Jun 29, 14:19 UTCJun 29, 18:40 UTC4h 21m
2026-06-28 UAL2641 SFO → SAN Jun 28, 21:59 UTCJun 29, 03:10 UTC5h 10m
2026-06-28 UAL316 - Jun 28, 13:04 UTCJun 28, 19:55 UTC6h 50m
2026-06-28 UAL316 DUB → DUB Jun 28, 12:50 UTCJun 28, 12:55 UTC5m
2026-06-28 UAL317 EWR → DUB Jun 28, 04:29 UTCJun 28, 10:15 UTC5h 45m
2026-06-26 UAL316 DUB → EWR Jun 26, 13:30 UTCJun 26, 20:15 UTC6h 45m
2026-06-26 UAL316 DUB → EWR Jun 26, 13:21 UTCJun 26, 20:16 UTC6h 55m
2026-06-26 UAL317 - Jun 26, 05:39 UTCJun 26, 11:24 UTC5h 45m
2026-06-26 UAL317 EWR → DUB Jun 26, 05:31 UTCJun 26, 11:20 UTC5h 49m
2026-06-25 UAL2248 SFO → EWR Jun 25, 22:49 UTCJun 26, 03:50 UTC5h 0m
2026-06-25 UAL648 - Jun 25, 15:24 UTCJun 25, 20:54 UTC5h 30m
2026-06-25 UAL887 - Jun 25, 08:04 UTCJun 25, 11:54 UTC3h 50m
2026-06-24 UAL886 EWR → LIM Jun 24, 18:50 UTCJun 24, 22:35 UTC3h 45m
2026-06-24 UAL886 EWR → LIM Jun 24, 18:53 UTCJun 25, 01:59 UTC7h 6m
2026-06-24 UAL2301 - Jun 24, 14:00 UTCJun 24, 15:29 UTC1h 30m
2026-06-24 UAL661 ORD → EWR Jun 24, 02:00 UTCJun 24, 02:05 UTC5m
2026-06-24 UAL661 ORD → EWR Jun 24, 00:09 UTCJun 24, 02:05 UTC1h 55m
2026-06-23 UAL661 ORD → EWR Jun 23, 23:42 UTCJun 24, 01:43 UTC2h 1m

About Mode-S

A Mode-S transponder code (also called an "ICAO 24-bit address" or "hex code") is a 6-character hexadecimal identifier permanently assigned to an aircraft when it's first registered. Unlike callsigns (which change with each flight) or registrations (which can change if an aircraft is sold internationally), the Mode-S address stays with the airframe for the life of the aircraft in that country.

Every ADS-B transmission from an aircraft includes its Mode-S address, making it the most reliable way to identify a specific airframe. Flight-tracking services like Apparatus use the Mode-S address as the primary key for tying position broadcasts, callsigns, and ownership records together.

Prefer a tail-number view? See the N58101 page for operator, model, and routing details .

Mode-S A77C11 frequently asked

What is Mode-S code A77C11?
A77C11 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N58101.
Where is Mode-S A77C11 registered?
Mode-S code A77C11 is allocated to United States (US). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is A77C11 broadcasting right now?
No active broadcast right now. Last signal was 3d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A77C11, octal 51676021, decimal 10,976,273.
What flights does A77C11 operate?
Mode-S A77C11 has broadcast 20 distinct callsigns, including UAL316, UAL270, UAL271, UAL912, UAL310.